Is Tribulus Terrestris an Effective Aphrodisiac?

Mounting evidence shows that this vine treats sex problems in both men and women

Mention aphrodisiac plants and few people cite Tribulus terrestris, commonly called puncture vine. But that’s changing as evidence accumulates that a leaf extract of this attractive ground-cover helps treat a variety of sex problems in women—low libido, arousal difficulties, lubrication problems, and orgasm troubles—and also possibly erectile dysfunction and infertility in men. Not all studies show benefit, and scientists still aren’t sure how the plant works, but Tribulusis safe in recommended amounts and the weight of current evidence tilts in favor of this herb as an effective sexual medicine.

Tribulus is native to Asia—Indians call it gokshura—but the plant grows in temperate locales worldwide, and sometimes so vigorously that it becomes an invasive pest. It has hairy leaves, yellow flowers, and fingernail-size fruits encased in hard nubby shells with one or more sharp, nasty thorns, hence its common name, puncture vine. Tribulus sends a long taproot deep into the soil, allowing it to find water and thrive in arid areas. Indian and Chinese herbalists have used it medicinally for centuries, and have long considered it an aphrodisiac. Western scientists scoffed—until they began testing it.

For Women: Many Sexual Benefits

Several studies show that a Tribulus leaf extract (7.5 to 750 mg/day for one to four months) enhances sexual function in women:

• Brazilian researchers gave a placebo or Tribulus (750 mg/day) to 36 postmenopausal women complaining of low libido. After four months, the placebo group reported scant improvement, but those taking Tribulus reported significantly increased desire, arousal, and lubrication, and greater likelihood of orgasm.

• Another Brazilian team gave either a placebo or Tribulus (750 mg/day) to 60 postmenopausal women complaining of sexual dysfunction. After four months, the Tribulus group reported significantly greater desire, easier arousal, greater self-lubrication, more comfortable intercourse, more orgasms, and enhanced sexual satisfaction.

• A third Brazilian group gave the herb (250 mg three times a day) to 120 women with low libido. One hundred six (88 percent) reported significant improvement.

• A fourth group of Brazilians gave either a placebo or Tribulus to 40 pre-menopausal women complaining of low desire. The placebo group showed no improvement, but those taking the plant extract showed significantly greater desire, arousal, lubrication, orgasms, and satisfaction.

Tribulus is less consistently effective for sex problems in men. A Brazilian study using 800 mg/day showed no benefit for treating erectile dysfunction (ED). But this study lasted only one month, possibly too short a duration to show benefit.

In a three-month study, Bulgarian researchers gave either a placebo or Tribulus (750 mg/day) to 180 men, age 18 to 65, with mild to moderate ED, some of whom also complained of low desire. The herb group showed significant improvement: more desire, firmer more reliable erections, and greater sexual satisfaction.

In addition, several studies show that in men suffering from infertility, Tribulus (750 to 1500 mgday) improves sperm motility and quality.

The Mechanism? A Mystery

Initially, researchers thought Tribulus boosted circulating levels of male sex hormones—testosterone in men and androgens in women. These hormones govern libido, and women taking the herb showed consistent improvement in desire. But some Tribulus studies tracked participants’ testosterone/androgens levels and results were inconclusive. In some trials, hormone levels increased, in others, they did not. In addition, supplemental testosterone does not help treat ED, but in the Bulgarian study, Tribulus improved erections in ED sufferers. Now researchers speculate that the plant increases the body’s synthesis of another compound critical to sexual function, nitric oxide.

In Western medicine, new treatments have difficulty getting accepted until scientists can explain their mechanism of action. The mechanism governing Tribulus remains elusive, so chances are the plant will continue to be controversial until researchers are confident they understand how it works.

Tribulus appears to be safe in recommended amounts, but some study participants dropped out due to side effects, typically stomach upset. If you try this herb, take 750 mg in divided doses (250 mg three times a day). If you notice any intestinal discomfort, reduce your dose or stop taking it.

Tribulus is an ingredient in many “sexual health” combination supplement blends, but usually at doses much lower than in the studies described above. If you’d like to try this herb, steer clear of combination products and go with just Tribulus. It’s available at most health food stores and herb shops, and on the Internet.

So far, all Tribulus research has taken place abroad, with none in the U.S. Compared with the rest of the world, American medical researchers tend to be more wedded to laboratory-synthesized drugs and less interested in traditional medicinal herbs. American scientists generally don’t investigate botanicals until they’ve shown considerable efficacy elsewhere. But as evidence mounts that Tribulus offers several sexual benefits, I look forward to American researchers investigating it.